According to a Penn State anthropologist, "male physical competition, not attraction, was central in winning mates among human ancestors." This was in line with Martin Daly's assertion of the importance of physical (as well as material) competition for men in an evolutionary context.

"Puts suggests that while a deep voice has been considered an appealing trait to women, it actually signals dominance...A low voice’s effect on dominance is many times greater than its effect on sexual attraction.”

This implies paradoxically (and perhaps with semantic inaccuracy) that women are motivated to have sex for reasons other than sexual attraction.

The second piece of research found that "cities that experienced greater growth in immigrant or new-immigrant populations between 1990 and 2000 tended to demonstrate sharper decreases in homicide and robbery." The research "suggests that, controlling for a variety of other factors, growth in the new immigrant population was responsible, on average, for 9.3 percent of the decline in homicide rates."

Hard to argue with the correlation, but the causal relation that "immigration may have been responsible for part of the precipitous crime drop of the 1990s" because "immigrant communities are often characterized by extended family networks, lower levels of divorce, and cultural and religious beliefs that facilitate community integration" seems much more tenuous.

In the 1990's, "many immigrants...settled in new growth states. Evidence from the 1990s, when California experienced an economic slowdown, suggests that jobs and higher wages drew many immigrants to other states, especially in the Rocky Mountain and Southeast regions. Public benefits do not appear to have driven these migration choices. In fact, California, Illinois, New York, and New Jersey rank among the most generous states in providing benefits to noncitizens, and most of the "new growth" states have relatively weak safety nets for immigrant families." (http://www.urban.org/publications/410589.html)

This suggests that areas that attracted immigrants had specific advantageous trends already underway that may have resulted in a reduction of crime even without the participation of immigrants. I had quoted Bob Dylan in my previous post, “when you got nothin’, you got nothin’ to lose.” The reverse should also hold.

I sent a note to Martin Daly to get his thoughts. Will post if he responds.

On a side bar, I should mention that though I had some questions about this particular analysis, I am strongly in favor of increased immigration. The reasons probably could make up a whole posting on their own, but I will be brief. The American competitive advantage is cultural. We are no smarter and no more hard-working than any other nation. Our genes are no different, and having seen our education firsthand as an intern teacher, our secondary education can be dramatically worse. If we are special, then it is only our culture that makes us so. In particular, our culture is highly attractive to talented knowledge workers in a way that is globally almost unique.

There is a disjoint between the frequent failure of our secondary education and our position as (and ambition to remain) the nation-leader in innovation, technology, and creativity. Have we ever asked ourselves how this is possible? How do people become so much smarter when they're in workforce, when they could barely do algebra in high school? The answer, if you look at the ethnic and national breakdown of our Ph.D. students, new entrepreneurs, and technologists, is immigration. Without immigration, the whole system falls apart. Yet we yank so hard at the linchpin that is the only thing holding our current preeminence together while we work desperately to fix our educational system in time.